cooling TOYOTA PRIUS 2023 Owners Manual

821-4. Hybrid system
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■ After the 12-volt battery has discharged or when the terminal has been
removed and installed during exchange, etc.
The gasoline engine may not stop even if the vehicle is being driven by the
hybrid battery (traction battery). If this continues for a few days, contact any
authorized Toyota retailer or Toyota authorized repairer, or any reliable
repairer.
■ Sounds and vibrations specific to a hybrid vehicle
There may be no engine sound or vibration even though the vehicle is able to
move with the “READY” indicator is illuminated. For safety, apply the parking
brake and make sure to shift the shift position to P when parked.
The following sounds or vibrations may occur when the hybrid system is
operating and are not a malfunction:
● Motor sounds may be heard from the engine compartment.
● Sounds may be heard from the hybrid battery (traction battery) under the
rear seats when the hybrid system starts or stops.
● Relay operating sounds such as a snap or soft clank will be emitted from the
hybrid battery (traction battery), under the rear seats, when the hybrid sys-
tem is started or stopped.
● Sounds from the hybrid system may be heard when the back door is open.
● Sounds may be heard from the transmission when the gasoline engine
starts or stops, when driving at low speeds, or during idling.
● Engine sounds may be heard when accelerating sharply.
● Sounds may be heard due to regenerative braking when the brake pedal is
depressed or as the accelerator pedal is released.
● Vibration may be felt when the gasoline engine starts or stops.
● Cooling fan sounds may be heard from the air intake vent. (P. 85)
■ Vehicle proximity notification system
In the following cases, the vehicle proximity notification system may be diffi-
cult for surrounding people to hear.
● In very noisy areas
● In the wind or the rain
Also, as the vehicle proximity notification system is installed on the front of
the vehicle, it may be more difficult to hear from the rear of the vehicle com-
pared to the front.
■ When “Proximity Notification System Malfunction Visit Your Dealer” is
displayed on the multi-information display
The vehicle proximity notification system may be malfunctioning. Have the
vehicle inspected by any authorized Toyota retailer or Toyota authorized
repairer, or any reliable repairer.

851-4. Hybrid system
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For safety and security
There is an air intake vent under
the right side of the rear seat for
the purpose of cooling the hybrid
battery (traction battery). If the
vent is blocked, charging/dis-
charging of the hybrid battery
(traction battery) may become lim-
ited.
When a certain level of impact is detected by the impact sensor, the
emergency shut off system blocks the high voltage current and stops
the fuel pump to minimize the risk of electrocution and fuel leakage. If
the emergency shut off system activates, your vehicle will not restart.
To restart the hybrid system, contact any authorized Toyota retailer or
Toyota authorized repairer, or any reliable repairer.
A message is automatically displayed when a malfunction occurs in
the hybrid system or an improper operation is attempted.
If a warning message is shown on
the multi-information display, read
the message and follow the
instructions.
Hybrid battery (traction battery) air intake vent
Emergency shut off system
Hybrid warning message

901-4. Hybrid system
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NOTICE
■Hybrid battery (traction battery) air intake vent
● Make sure not to block the air intake vent with anything, such as a seat
cover, plastic cover, or luggage. If the vent is blocked, the charging/dis-
charging of the hybrid battery (traction battery) may become limited.
● When dust etc. has accumulated in the air intake vent, clean it with a vac-
uum cleaner to prevent the vent from clogging.
● Do not get water or foreign materials in the air intake vent as this may
cause a short circuit and damage the hybrid battery (traction battery).
● Do not carry large amounts of water such as water cooler bottles in the
vehicle. If water spills onto the hybrid battery (traction battery), the battery
may be damaged. Have the vehicle inspected by any authorized Toyota
retailer or Toyota authorized repairer, or any reliable repairer.
● There is a filter installed to the air intake vent. When the filter remains
noticeably dirty even after cleaning the air intake vent, filter cleaning or
replacement is recommended. For information regarding filter cleaning or
replacement, refer to P. 545.
● If “Maintenance Required for Traction Battery Cooling Parts See Owner's
Manual” is shown on the multi-information display, the air intake vent and
filter may be clogged. Refer to P. 545 for information on how to clean the
air intake vent.

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4-6. Driving tips
Driving
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Hybrid vehicle driving tips
◆Using Eco drive mode
When using Eco drive mode, the torque corresponding to the accel-
erator pedal depression amount can be generated more smoothly
than it is in normal conditions. In addition, the operation of the air
conditioning system (heating/cooling) will be minimized, improving
the fuel economy. (P. 351)
◆Use of Hybrid System Indicator
The Eco-friendly driving is possible by keeping the Hybrid System
Indicator within Eco area. (P. 132)
◆Shift position operation
Shift the shift position to D when stopped at a traffic light, or driving
in heavy traffic etc. Shift the shift position to P when parking. When
using the N, there is no positive effect on fuel consumption. In the
N, the gasoline engine operates but electricity cannot be gener-
ated. Also, when using the air conditioning system, etc., the hybrid
battery (traction battery) power is consumed.
◆Accelerator pedal/brake pedal operation
●Drive your vehicle smoothly. Avoid abrupt acceleration and
deceleration. Gradual acceleration and deceleration will make
more effective use of the electric motor (traction motor) without
having to use gasoline engine power.
●Avoid repeated acceleration. Repeated acceleration consumes
hybrid battery (traction battery) power, resulting in poor fuel con-
sumption. Battery power can be restored by driving with the
accelerator pedal slightly released.
For economical and ecological driving, pay attention to the fol-
lowing points:

4605-1. Using the air conditioning system and defogger
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Press .
Adjust the temperature setting. (P. 458)
Press .
The cooling and dehumidification function switches between on and
off each time is pressed.
To stop the operation, press .
When in automatic mode, the air outlet modes and fan speed levels
are not displayed in the air conditioning control panel display.
■Automatic mode indicator
If the fan speed setting or air flow modes are operated, the
indicator goes off. However, automatic mode for functions other
than that operated is maintained.
■Adjusting the temperature for driver and passenger seats sep-
arately (DUAL mode)
To turn on the DUAL mode, perform the following either operation:
●Press .
●Adjust the temperature setting of the passenger side with the
passenger side temperature adjustment knob.
The indicator illuminates when the DUAL mode is on.
Using automatic mode
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4665-1. Using the air conditioning system and defogger
PRIUS_OM_OM47F32E_(EE)■Operation of the air conditioning system when the blower customization
is set to “ECO”
●In the “ECO” mode, the air conditioning system is controlled as follows to
prioritize fuel efficiency:
• Engine speed and compressor operation controlled to restrict heating/
cooling capacity
• Fan speed restricted when automatic mode is selected
●To improve air conditioning performance, perform the following operations:
• Adjust the fan speed
• Adjust the temperature setting
• Set the blower customization to “FAST” or “NORMAL” mode.
●When the driving mode is set to Eco driving mode, the fan speed setting
mode will be changed to “ECO” mode automatically. Even in this case, the
fan speed control mode can be changed by pressing . (P. 351)
■When the outside temperature falls to nearly 0C (32F)
The dehumidification function may not operate even when is pressed.
■Ventilation and air conditioning odors
●To let the fresh air in, set the air conditioning system to the outside air mode.
●During use, various odors from inside and outside the vehicle may enter into
and accumulate in the air conditioning system. This may then cause odor to
be emitted from the vents.
●In order to suppress odors that occur when the air conditioning system
starts, fresh air is automatically taken in when parked.
●To reduce potential odors from occurring, the start timing of the blower may
be delayed for a short period of time immediately after the air conditioning
system is started in automatic mode.
■Air conditioning filter
P. 542
■Customization
Settings (e.g. outside/recirculated air mode) can be changed.
(Customizable features: P. 670)

5096-3. Do-it-yourself maintenance
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Maintenance and care
WARNING
The engine compartment contains many mechanisms and fluids that may
move suddenly, become hot, or become el ectrically energized. To avoid death
or serious injury, observe the following precautions.
■ When working on the engine compartment
● Make sure that the “Accessory”, “Ignition ON” or mileage display (P. 118,
120) on the main display and the “READY” indicator are both off.
● Keep hands, clothing and tools away from the moving fan.
● Be careful not to touch the engine, power control unit, radiator, exhaust
manifold, etc. right after driving as they may be hot. Oil and other fluids
may also be hot.
● Do not leave anything that may burn easily, such as paper and rags, in the
engine compartment.
● Do not smoke, cause sparks or expose an open flame to fuel. Fuel fumes
are flammable.
● Be extremely cautious when working on the 12-volt battery. It contains poi-
sonous and corrosive sulfuric acid.
● Take care because brake fluid can harm your hands or eyes and damage
painted surfaces. If fluid gets on your hands or in your eyes, flush the
affected area with clean water immediately. If you still experience discom-
fort, consult a doctor.
■ When working near the electric cooling fans or radiator grille
Be sure the power switch is off.
With the power switch in ON mode, the electric cooling fans may automati-
cally start to run if the air conditioning is on and/or the coolant temperature
is high. ( P. 520)
■ Safety glasses
Wear safety glasses to prevent flying or falling material, fluid spray, etc.
from getting in your eyes.

5146-3. Do-it-yourself maintenance
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Engine compar tment
Engine coolant reservoir
( P. 518)
Fuse boxes ( P. 557)
Engine oil level dipstick
( P. 515)
Engine oil filler cap ( P. 516)
12-volt battery ( P. 521)
Power control unit coolant
reservoir ( P. 518)
Radiator ( P. 520)
Condenser ( P. 520)
Electric cooling fans
Washer fluid tank ( P. 526)
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5196-3. Do-it-yourself maintenance
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Maintenance and care
■Coolant selection
Only use “Toyota Super Long Life Coolant” or a similar high quality ethylene
glycol based non-silicate, non-amine, non- nitrite, and non-borate coolant with
long-life hybrid organic acid technology.
“Toyota Super Long Life Coolant” is a mixture of 50% coolant and 50% deion-
ized water. (Minimum temperature: -35 C [-31F])
For more details about coolant, contact any authorized Toyota retailer or
Toyota authorized repairer, or any reliable repairer.
■ If the coolant level drops within a short time of replenishing
Visually check the radiator, hoses, engine/power control unit coolant reservoir
caps, drain cock and water pump.
If you cannot find a leak, have any authorized Toyota retailer or Toyota autho-
rized repairer, or any reliable repairer, test the cap and check for leaks in the
cooling system.
WARNING
■ When the hybrid system is hot
Do not remove the engine/power control unit coolant reservoir caps.
The cooling system may be under pressure and may spray hot coolant if the
cap is removed, causing serious injuries, such as burns.
NOTICE
■ When adding coolant
Coolant is neither plain water nor straight antifreeze. The correct mixture of
water and antifreeze must be used to provide proper lubrication, corrosion
protection and cooling. Be sure to read the antifreeze or coolant label.
■ If you spill coolant
Be sure to wash it off with water to prevent it from damaging parts or paint.

5206-3. Do-it-yourself maintenance
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Check the radiator and condenser and clear away any foreign objects.
If either of the above parts is extremely dirty or you are not sure of
their condition, have your vehicle inspected by any authorized Toyota
retailer or Toyota authorized repairer, or any reliable repairer.
Radiator and condenser
WARNING
■ When the hybrid system is hot
Do not touch the radiator or condenser as they may be hot and cause seri-
ous injuries, such as burns.
■ When the electric cooling fans are operating
Do not touch the engine compartment.
With the power switch in ON mode, the electric cooling fans may automati-
cally start to run if the air conditioning is on and/or the coolant temperature
is high. Be sure the power switch is off when working near the electric cool-
ing fans or radiator grille.